Dual completion tool



W 26, 1966 c, E. WAKEFIELD, JR 3,247,904

DUAL COMPLETION TOOL 3 Sheets-Sheet 1 Filed April l, 1965 April 26, 1966 c. E. WAKEFIELD, JR

DUAL COMPLETION TOOL 5 SheetsSheet 2 Filed April l. 1963 M WM 47m/@Mfr prll 269 w66 c. E. WAKEFIELD, JR 3,247,904

DUAL COMPLETION TooL Filed April 1, 1963 -heets-Sheet 3 United States Patent 3,247,904 DUAL CMPLEHGN 115011 Charles E. Wakefield, Jr., lairerslield, alif., assigne-r to Richfield @il Corporation, Los Angeles, alif., a corporation of Delaware Filed Apr. 1, 1963, Ser. No. 269,517 6 Claims. (Cl. 1166-116) The present invention relates to an apparatus for producing a multiple zone oil bearing formation and, more particularly, relates to an apparatus for separately producing a plurality of productive zones in an oil bearing formation through a single well.

lt is desirable to produce the individual zones in an oil bearing formation separately in order to meet the individual requirements of the zones and to prevent the dissipation of well production and pressure through lower pressure zones. It is generally desirable to separate one or more zones from each other, particularly gas zones from oil zones, since the zones may be under different pressures, in which case simultaneous production would tend to produce the higher pressure zones into the lower pressure zone. Through the use of a dual completion tool several zones may be completed through a single well bore by appropriate separation of the various zones, thus saving the cost of drilling additional wells.

Dual completion tools have been designed heretofore, however, many of them produce one of the zones through the casing annulus and thus it is impossible to pack off the casing annulus above the upper producing zone to thereby avoid having zone pressure on the casing lat the surface. With the upper zone properly packed off in the casing annulus, the casing provides secondary protection and permits improved production since the volume above the producing zone is limited. ri`he use of a storm choke to seal off a zone when the flow therethrough exceeds a certain value cannot be used for each production zone if one of the zones is produced in the casing annulus.

Other prior art proposals for dual completion require the use of specially designed drilling heads in order to manipulate the Well equipment for the various zones to position an inner string perforation adjacent other equipment previously located in the well zone. These prior rart devices also require generally that two or more strings be run together, which has the disadvantage of requiring the operator to predict at the time that the first zone is produced whether other zones may be produced. in the event that the operator does not run the second string of tubing, it is then necessary for the dual completion mandrel to be retrieved when it is found desirable to run a second string of tubing.

it is, therefore, an object of the present invention to provide `a dual completion tool whereby storm choke apparatus can be utilized on each tubing string.

It is also an object of the present invention to provide a dual completion apparatus whereby the well can be packed off above the upper zone.

lt is a further object of the present invention to provide a dual completion apparatus whereby each zone can be produced individually.

1t is also an object of the present invention to provide a dual completion apparatus utilizing a plurality of strings which can be run either separately or together.

It is also an object of the present invention to provide a dual completion apparatus which can be utilized with the conventionally designed well head equipment.

It is lalso an object of my present invention to provide a dual completion tool whereby the lower zone may be produced through the outer string and the upper zone produced in the inner string without damaging the outer string.

iligllhd Patented Apr., 26, 1966 It is another object of the present invention to provide a dual completion tool whereby a lower zone can be lifted with an upper zone or vice versa.

lt is a further object of my present invention to provide a dual completion tool to which an Aadditional tubing string can be added without rst recovering the original tubing string and the dual completion mandrel from the well.

Other objects and a more complete understanding of the present invention may be had by reference to the following specification and claims taken in conjunction with the following drawings, wherein:

FIG. l shows in sectional elevation the dual completion mandrel of my present invention installed in a well bore in a tubing string;

FIG. 2 shows a cross-sectional view of the section taken on 2-2 of FIG. 1;

FiG. 3 shows in sectional elevation the modified form of my present invention utilized as `a gas lift device;

FIGS. 4a and 4b show an enlarged sectional view of the tubing safety valve of FlG. 1.

With reference to the drawings generally, the dual completion mandrel of my present invention is shown installed in a tubing string itl in a cased well drilled in a multiple zone formation. The mandrel permits as shown by the arrows in FIG. 1 production of the lower zone 18 of the formation through the outer string 10 and production of the upper zone 16 through the inner string 30 with the two zones being separated from each other by a packer 2li and the upper zone being isolated from the casing up to the surface by a packer 22.

Referring more particularly now to FIG. 1, a conventional tubing string 1t) is provided with a dual completion mandrel 12 which may be threadably interconnected with the tubing string ill or by any conventional means. The tubing string 1t) is shown positioned in a well bore drilled into a multizone formation having producing zones 16 and 18 and provided with casing 14. The zones 16 `and 13 are separated by packer 20 and the well bore preferably packed oli above the upper zone 16 by a packer 22.

The mandrel 12 has an inner barrel 24 which is in communication with the production of zone 16 through the .radial ports 26, as best shown in FiG. 2. As shown in FlG. 2, the member 28 delining the ports provides the means for supporting the inner barrel 245 within the mandrel 1?.. The dual completion mandrel 12 is designed so that the ilow from the upper zone through the inner string does not flow directly against the inner string 24, thus protecting the inner string 24 from the im-pingement of sand, etc. entrained in the production fluid of zone 16, which impingement normally causes erosion of the inner tubing, thus requiring repair or replacement of the tubing or mandrel. As can be seen in FIGS. 1 and 3, the production from zone 16 entering the port 26 is flowing against production from the other side of the mandrel or, in other words, in the case where zone 16 is a gas zone, gas is owing against gas into the inner string rather than gas iowing directly against the inner string. The flow into the port 26 passes upward through the inner string 2d and may be yproduced through a macaroni or inner string 36, thereby producing zone 16 independent of the other zone(s) in the formation.

The inner macaroni string 36 may be run with the tubing string 1li by presetting the macaroni string 30 in the inner string 2li of the mandrel with a packing element or seal 32. The macaroni string may be run into the mand-rel after the mandrel is run with the tubing string 1l) by stabbing the macaroni string into the upper end 34 of the inner string 24 of the mandrel. Inner barrel 24 is preferably concentric with mandrel 12 and the tubing string to facilitate stabbing macaroni string 30 into the inner barrel without pulling the mandrel to the surface.

The production strings through which each individual zone is produced may be provided with a conventional storm choke or tubing safety valve which is adapted to close should the ow line or either of the production tubing strings break. Storm chokes 36 and 3S are provided in the tubing string 10 and macaroni string 30, respectively, used to produce the zones 16 and 18. A typical storm choke as shown in FIGS. 4a and 4b is equipped with a spring loaded check valve which closes when the flow through the valve exceeds a certain value and overcomes the resistance of the spring.

By providing latch nipples in each string it is possible to selectively set a plug in each string in order to work each zone separately. These latch nipples then receive the storm chokes when desired. For example, storm choke 3S' may be attached to a conventional latching mandrel which latches into the latch nipple section 50 of the inner barrel. FIGS. 4a and 4b show a suitable storm choke arrangement where a latch nipple 50 is provided in the tubing string 10 and a locking dog 54- of landing mandrel 56 seated within nipple S0 on shoulder 58 to support the mandrel therein. A tubing safety ,valve or storm choke assembly 60 is then connectedv to the landing mandrel 56 with a bean 62. The safety valve assembly, landing n-ipple, and mandrel are conventional equipment, such as are produced by the Otis Engineering Corp.

In the apparatus shown in FIG. 4b, the valve element 36 (also shown diagrammatically in FIG. l) is held offseat by spring 66 until the flow from the well reaches a predetermined rate. When the pressure across bean 68 exceeds the spring tension, the valve closes, thus preventing ow through ports '70. The valve 36 is reopened b pressure from the surface.

FIG. 3 shows an adaptation of my present invention to provide a tool for lifting the lower zone with an upper gas producing zone 40. For this application the two zones, although separated with packer 20, are produced together through tubing string 10. Hence, a conventional combination of gas lift valve or bean and storm choke 42 is provided in the inner barrel 24 of the mandrel so that the gas from the zone 40 passing through the inner barrel of the mandrel may be used to lift oil from a lower zone, e.g. zone 44, in the conventional manner.

By my present invention, the packer separating the distinct zones 16 and 18 or 40 and 44, is required; however, it is also desirable to use a packer 22 above the upper zone 16 since the casing annulus is not used for production with the dual completion tool of my present invention. The upper packer 22, although not strictly necessary with my present invention, may advantageously be used to prevent the casing at the surface from being subjected to zone pressure, thus permitting the casing to serve as a secondary protection for the well production tubing. Packer 22 is also desirable from the standpoint of decreasing the working volume above the zone since a well is known to produce better with packers since the volume into which the production ows is not as large.

With the apparatus shown and described it is possible to run the packers on the tubing string. This, of course, is possible because of the use of concentric tubing strings. Concentric strings are not absolutely necessary with my present invent-ion as parallel strings can be used with a dual packer.

Since the dual completion mandrel of my present invention does not require the registering or alignment of ports, it is possible to use my dual completion mandrel with conventional well head equipment.

Although my present invention has been described with a certain degree of specificity, it is to be understood that departures can be made from the specific embodi- 4- rnents disclosed without departing from the essence of my invention` which is defined by the following claims.

I claim: 1. An apparatus for producing a cased well from an 5 upper and a lower production zone through a tubing string comprising:

a dual completion mandrel connected to and in fluid communication with said tubing string, said mandrel having an inner barrel integral with said mandrel,

tubular means forming a passageway through said mandrel into said inner barrel for producing said upper zone through said inner barrel of said mandrel,

means for packing off the annulus between said tubing string and said well above said mandrel and said production zones, v

packing means positionable intermediate said zones in the annulus between the well casing andb said tubing for separating said zones, and

means for producing said lower zone through said mandrel and said tubing string.

2. The apparatus of claim 1 wherein a storm choke is positioned in said tubing string and in said inner barrel.

3. An apparatus for producing a cased well from a plurality of production zones through a tubing string and a macaroni string, comprising:

a dual completion mandrel connected to and in tluid communication with said tubing string, said mandrel having an inner barrel integral with said mandrel, said inner barrel being adapted for receiving an inner string therein through said tubing string,

tubular means forming a passageway through said mandrel into said inner barrel for producing sa-id upper zone through said inner barrel of said mandrel,

means for packing off the annulus between said tubing string and said well above said mandrel and said production zones,

packing means positionable intermediate lsaid zones in the annulus between the well casing and said tubing for separating said zones, and

means for producing said lower zone through said mandrel and said tubing string.

4. An apparatus for producing a cased well from aA plurality of production zones through a tubing string, comprising:

a dual completion mandrel connected to and in fluid communication with sa'id tubing string,

a macaroni string positioned within said tubing string and extending into said mandrel,

said mandrel having an inner barrel integral with said mandrel,

tubular means forming a passageway through said mandrel into said inner barrel for producing said upper zone through said mandrel and said macaroni string,

means for packing off the annulus between said tubing string and said well above said mandrel and said production zones,

packing means positionable intermediate said zones in lthe annulus between the well casing and said tubing for separating said zones,

means for conning flow into said tubular means to said macaroni string, and

means for producing said lower zone through said mandrel and said tubing string.

5. An apparatus for producing through a tubing string and a macaroni string a cased well from an upper and a lower production zone separated by packing means, comprising:

a dual completion mandrel connected to and in fluid communication with said tubing string, said mandrel having an inner barrel integral with said mandrel and communicating with said macaroni string, packing means positionable intermediate said zones in the annulus between the well casing and said tubing,

a horizontally disposed tubular member having a vertical opening therein communicating with said inner bar-rel for producing said upper zone through said inner barrel of said mandrel whereby the production from said upper zone ows directly into said inner barrel, and

means for producing said lower zone through said mandrel and said tubing string.

a horizontally disposed tubular member having a vertical opening therein communicating with said inner barrel for producing said upper zone through said inner `barrel of said mandrel whereby the production from said upper zone ows directly into said inner barrel, and

means for producing saidlower zone through said mandrel and said tubing string.

6. An apparatus for producing through a tubing string and a macaroni string a cased well from an upper and 1U a lower production zone separated by packing means, comprising:

References Cited by the Examiner UNITED STATES PATENTS a `dual completion mandrel connected axially Within Said tllblllg String and postionable adjacent `(osline X said upper production zone and communicating 15 2368428 1/1945 Saurenmgl; 166 114 therewith, said mandrel having an inner barrel 8701.843 1/1959 Rodgers :166 146 X integral with said mandrel and communicating with 42,972,379 2/1961 Brown 166121 X said macaroni string, packing means positionable 2,978,031 4/1951 Grimmer 155 114 intermediate said zones in the annulus between the well casing and said tubing, 20 CHARLES E. OCONNELL, Primary Examiner. 

1. APPARATUS FOR PRODUCING A CASED WELL FROM AN UPPER AND A LOWER PRODUCTION ZONE THROUGH A TUBING STRING COMPRISING: A DUAL COMPLETION MANDREL CONNECTED TO AND IN FLUID COMMUNICATION WITH SAID TUBING STRING, SAID MANDREL HAVING AN INNER BARREL INTEGRAL WITH SAID MANDREL, TUBULAR MEANS FORMING A PASSAGEWAY THROUGH SAID MANDREL INTO SAID INNER BARREL FOR PRODUCING SAID UPPER ZONE THROUGH SAID INNER BARREL OF SAID MANDREL, MEANS FOR PACKING OFF THE ANNULUS BETWEEN SAID TUBING STRING AND SAID WELL ABOVE SAID MANDREL AND SAID PRODUCTION ZONES, PACKING MEANS POSITIONABLE INTERMEDIATE SAID ZONES IN THE ANNULUS BETWEEN THE WELL CASING AND SAID TUBING FOR SEPARATING SAID ZONES, AND MEANS FOR PRODUCING SAID LOWER ZONE THROUGH SAID MANDREL AND SAID TUBING STRING. 